New member introduction - System three interest

[David Richards]

Greetings, David here.

I'm a volunteer at the local vintage computer collection where we have recently acquired some Cromenco System three systems, I am hoping to get at least one into working condition for a demonstration.

I live in RIllington, North Yorkshire, UK. The local museum is the 'Jim Austin Computer Collection' at Fimber, UK https://www.computermuseum.org.uk/

The situation at present is that we have one system box power supply working and next we shall check the individual S100 boards and try and boot a minimal system.

In preparation I have configured a Gotek with flash floppy and a 5 1/4 boot disk image. The system we have has a 5 1/4 inch drive fitted together with some boot disks of unknown status. I thought using a gotek would eliminate some variables until we have a working system.

Best regards, David.

[Mike Arnold]

David,

Welcome to the group and congratulations on your start of a Cromemco journey. There are many people in the group who can guide and assist.

If you decide you want a working physical boot disk I can always post you one. I can do all formats. Sorry, don't have a Gotek so cannot advise but others on the forum have extensive experience.

You say that the System three has a 5 1/4in floppy drive which implies that it has been modified as they were shipped with 8in drives. Also, if your S100 cards have socketed chips then only about half will be working (the other half can be fixed but it is a laborious task).

I am in south Manchester so not a million miles away. Happy to chat on the phone if you need.

Mike

[Mike Stein]

Hi David, and welcome to the ever so friendly Cromemco world! ;-)

As my namesake says, although they had provision for an external 5 1/4" drive the System 3s came with one or two 8" drives, either the two-bay CS-3 with one or two Persci dual drives or a single bay CS-3A with a Tandon TM848 and a hard disk. I'm going to guess that yours is/are the CS-3 with the unreliable Persci drives replaced with 5 1/4 drive(s) in an adapter plate.

The operating systems that you can run (CDOS, CP/M, Z80 Cromix or 68000 Cromix) will depend on the actual cards.

How about some pictures and a list of the cards that you have, so we can know what we're talking about?

Lots of luck and, above all, have fun!

(The other) mike

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[Roger Hanscom]

Hi David,

>>  Sorry, don't have a Gotek so cannot advise but others on the forum have extensive

>>  experience.

I'm running a System 1 with Gotek as drive A:.  I can boot CDOS, CP/M, or Z80 Cromix from it.  I can e-mail the Gotek files if you want, and when you are ready for them.

Roger

[David Richards]

Thanks all for the encouraging words, much appreciated.

Roger, I would very much appreciate a know set of working files for my Gotek ( I'm running FlashFloppy s/w if that makes a difference. I usually use it on my Alphatronic CP/M machine)

We have not yet made an inventory of the cards fitted, there are several Cromemco machines, mainly with 8 inch drives. 

The system we are starting with has the 8 inch drives replaced with a single 5 1/4 Mitsubishi MF504B-312M.

There are some disks which came with it but I'm reluctant to try them until the drives have been cleaned.

Initially I was going to take images of the disks but when I found archives of disks available online I thought the Gotek would be preferable for initial testing. 

On my next visit in a weeks time, I'll take photos and post them here. I'll find out about the history and post a resume too, they were taken from their place of work for many years.
Best regards, David.

[Peter Higgins]

The Mitsubishi MF504B is an HD 5.25" drive - likely the previous owner used this as a modern substitute for an 8" drive.

Your plan to connect a Gotek (emulating an 8" drive) is great, and booting the system (assuming the hardware works) using Roger's disk image files for the Gotek will really help get you going.

[Roger Hanscom]

OK ... seems that there is some interest in my working and bootable flash floppy stuff, so I'll work on dumping the flash sticks and posting them here.  I use 3 different sticks (CDOS, CP/M, and Z80 Cromix), but maybe it would be possible to combine them into one?  Don't know -- never tried it.  David, I am also using the flash floppy software.

Mike, it's been a while since I've done this, so bear with me.  To copy material (files) to the flash stick, I found it's easiest to use the Sydex DOS program "ANADISK".  Are you familiar with it?  There is an option to dump the content of a diskette into a single file.  So, get the software that you want to copy onto floppies, and dump them with ANADISK  There is an option to dump without the sector headers.  I think the header contains the cylinder and sector numbers among other things. You don't want that, nor do you need that.  Just produce a raw image of the diskette -- just a bunch of sector images.  There are many other ways to produce a sector dump of the content of a diskette, so maybe you know of easier ways to do it (in WinDoze?)?  I think that it might even be possible to use DD on a Linux (or Unix) box?

Anyway, those files (the raw sector dumps) get copied to the flash stick with recognizable names, or diskette numbers (as the name).  Then you just select the file (diskette) you want by using the selector buttons on the face of the Gotek.  The beauty of it is you can just change "diskettes" by using the buttons on the Gotek display.  It's really easy, once you understand what is required.  The Gotek, with flash floppy s/w, just views these raw disk dump files as a collection of sectors.

Oh, and I should mention that I've gone completely to 5.25" HD diskettes (1.2MB) on my Cromemcos (the Cromemco hardware thinks that they are 8" drives!!  <grin>).  The image files on the flash stick must (absolutely MUST) match the disk drive geometry.  If you are wanting to use 360k floppies, then we'll have to think about how to do that.  I just don't use that format anymore.

Stay tuned for dumps of my flash sticks.

Roger

[Roger Hanscom]

There's a couple of things I didn't say.  I made the tiny OLED mod to my Gotek.  I find it very helpful.  There are mods. available to add sound to the Gotek, and to add a knob to select .DSK files instead of using the buttons.  I didn't go for the sound or knob.  Didn't seem to be terribly useful.  YMMV.

Also, once you get a .DSK file to function, then you can mount the flash stick on your PC (it mounts as vfat), duplicate the .DSK file (once or many times), and then you can erase the content of the duplicated files on the Cromemco (ERA *.*).  If you have a real floppy drive on the Cromemco, you can copy files to/from the floppy disks to the Gotek in the usual way.

Thinking about creating a .DSK file, I remembered that the ANADISK approach is a good one because it can adapt to the funky format of Cromemco diskettes, i.e. switch from the SD boot track, to the remaining DD content of the diskette.  Other applications may not be able to do that?  

Here are the files I use to boot up CDOS.

Roger

[Roger Hanscom]

Here's the CP/M stuff.  It is the very nice implementation of version 2.2 by ITC (Intelligent Terminals Corp.???).  The boot up is a two stage thing.  A minimal system first loads from the boot track of the floppy, and then it gets expanded to a fully functioning system using the file CPMLOAD.COM on the diskette.  That file has to be there for the boot to work.  Don't erase it!

ITC.DSK is a copy of the ITC software distribution diskette.

[Roger Hanscom]

Here's the Z80 Cromix stuff.  When I first started working with it, I had trouble with multiple boots.  It would boot the first time, but wouldn't ever boot again.  It was almost as if Cromix was modifying the .DSK file.  After a while the problem went away, and I never quite figured out what had happened.  I finally figured out that I ought to have a back-up copy of the .DSK file so that I could recover after a second boot failed.  It might be a good idea to do that with all of the O.S. Gotek flash sticks.  Just call the back-up "back.sav" (lower case).  It won't get in the way of anything, and the capacity of your average flash stick is immense compared with the size of a .DSK file, so space isn't a problem.

Oh, and remember -- the Gotek looks like an 8" disk drive to the Cromemco hardware, so reply to the boot-up dialog accordingly.

[Mike Stein]

Wow! Thanks ever so much, Roger!

Can't wait to try out those images.

m

On Fri, Nov 7, 2025 at 11:55 AM Roger Hanscom <norwe...@gmail.com> wrote:

Here's the Z80 Cromix stuff.  When I first started working with it, I had trouble with multiple boots.  It would boot the first time, but wouldn't ever boot again.  It was almost as if Cromix was modifying the .DSK file.  After a while the problem went away, and I never quite figured out what had happened.  I finally figured out that I ought to have a back-up copy of the .DSK file so that I could recover after a second boot failed.  It might be a good idea to do that with all of the O.S. Gotek flash sticks.  Just call the back-up "back.sav" (lower case).  It won't get in the way of anything, and the capacity of your average flash stick is immense compared with the size of a .DSK file, so space isn't a problem.

Oh, and remember -- the Gotek looks like an 8" disk drive to the Cromemco hardware, so reply to the boot-up dialog accordingly.

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[David Richards]

Thank you Roger,

I agree the oled mod is most useful, I pimped up my first gotek with rotary encoder, sound, and oled but it's actually more convenient to just use the buttons and the sound doesn't add much.

As far as  can tell a single FF.CFG and IMG.CFG is suitable for all the images you have posted - there is a minor difference in one of the FF.CFG files but I suspect its accidental.

I'm looking forward ow to trying these, maybee look for an emulator to prepare myself beforehand.

I have ff v3.42 on this gotek, it was current last time I used it. 

I put the image files into subdirectories and copied one set of configuration files into the root of the USB memory stick, everything seems ok

Best regards, David.

[Roger Hanscom]

Thanks David.  I hope that the Gotek stuff works for you guys.  It has helped me distance myself from floppy drives, although not completely.  Seems that all of mine are either dead or dying.  <frown>

Roger

[David Richards]

As an aid to getting familiar with the Cromemco operating systems I've just built the Z80pack cromemco simulator - it 'just worked' too without any bother, very impressive.

Seeing the front panel simulation reminded me that there may be one of those in the collection - Nice if there is.

[David Richards]

Today I visited the Cromemco systems and took some photos of the boards and borrowed one of the system manuals. hopefully I'll be ready to test a small system at the weekend.

Photos here: https://djrm.net/Cromemco

In one system it looks like there are:

Z80 CPU card

Floppy disk interface with boot rom

2x four port serial cards (look very similar)

3x memory cards (all different)

In addition the other system has

battery backed clock card 

active termination card

and more ...

There are some dodgy looking PerSci 8 inch floppy drives too.

I'll cross reference the jumper settings, then check the power supplies on the boards next.

Sorry about the image quality, I need to re shoot with a shorter lens with working autofocus.

Best regards, David.

[Mike Arnold]

You seem to have a good selection of cards and from what I can see you have a very good chance of booting CDOS and probably Z80 Cromix without any "fettling". My suggestions are:

Use the 256KZ or the 64KZ-II for RAM. Leave the old 64KZ (with the big black heat sink) to one side for the time being. The 16FDC looks soldered so that should be ok. The ZPU may be tetchy but pressing all the chips into their sockets may be all it needs. Start with just those three cards and a floppy drive (Gotech) and you will have enough to boot CDOS. You must switch up the RAM correctly.

Incidentally, the TUART is two serial and two parallel ports and I have personally found it very useful.
Mike

[David Richards]

Mike, yes of course, the TUART cards are two parallel and two serial each. 

The manual I've bought back doesn't have the KZ memory card information just the one with big HS, perhaps its available on the cromemco github.

...

[Mike Stein]

Looks like a serious system; any idea what it was used for?

I'm curious: there are 10 DB-25s on the back panel, plus the 5.25 external drive connector; 8 TUART ports and 1 FDC port; what's the tenth one for?

The Persci voice coil drives were remarkably fast for their day, almost as fast as contemporary HDs; unfortunately they proved to be somewhat unreliable and difficult to maintain. 5 1/4HD disks and drives are almost 100% compatible with 8" versions (as are certain models of 3 1/2" drives) and can be used as replacements.

Looks like the system was running multi-user Cromix but that would probably require more than one drive, so at least one of the Perscis was probably in use; I believe Roger has a 4.8MB Cromix system running on Goteks and 'real' 5 1/4HD drives.

On the other hand,it almost looks like the system might have had an SMD hard disk drive that was perhaps removed for security reasons?

Looks like you're going to have lots of fun; by all means keep us posted!

m

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[David Richards]

I have asked for more information about the history of the units, they were used in a multi-user business system together with some test additional hardware. There are many more systems, manuals, and disks available but not yet catalogued. 

I have found lots of manuals on github, need to work out the correct jumper settings for the ram card.

[Roger Hanscom]

>> I believe Roger has a 4.8MB Cromix system running on Goteks and 'real' 5 1/4HD drives.

Correct -- Z80 Cromix.  Running with the Gotek as primary drive, and three 5.25" HD drives in an ancient System One.

I haven't been able to boot my XPU in a long time, so 68K Cromix is out of the question right now.

[David Richards]

An initial note received about the history of the systems in the collection has been added to my photo archive here: https://djrm.net/Cromemco/

I shall post here also when full details with photos become available. 

[Mike Stein]

Thanks for the extra effort of documenting these systems and their history; often their provenance is as interesting as their hard- and software, especially these systems and their unusual custom applications.

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